I get into this page probably too late to have any ideas included in upcoming version, but anyway few quick thoughts ...

Units:

1) there should be possibility to fire at specific hex, even if there is no unit visible in this hex for some class of units - like artillery, bombers, etc.
2) it would be nice if morale would be included for units - impacting the way they are fighting, etc.
3) it would be nice to include in prestige calculations recovered equipment, ex. when tanks are destroyed, and you hold the terrain where the remains exists for some time, they can be recovered, and used again after some necessary repairs

Terrain:

1) it would be nice to have possibility of destroying some parts of terrains, like bridges, buildings, dams, etc. with some impact on surrounding terrain (water flood for dams for ex)
2) it would be nice to have possibility of creating some parts of terrain, like bridges, buildings

Campaign:
1) It would be nice to have a possibility to rename, change type, along with possibly other unit parameters, and create, or destroy units in inventory between the scenarios in campaign
2) It would be nice to define specific number of each equipment type available to be bought for next scenario in campaign, for ex. to limit the number of specific tank types available in scenario
3) it would be great to have a possibility of predefined placement for the units in inventory - to make scenario starting positions more historical accurate
4) it would be greate to have possibility to define hierarchy for units,ex. 15. Panzer Division - 8. Panzer Regiment - I. Bataillon, etc. with unit badges, holding for ex. the historical symbols of units

Editor:

1) It would be nice to have a possibility of defining area, and filling it with some type of terrain, using potentially some random generator, ex. basic terrain type: desert, randomly on the same are, other types of terrain with predefined probability
2) it would be nice to define set of units to be copied between scenarios (especially for campaign creating)
3) it would be nice to have "clone" operation available for units, for ex to create minefields, but not only - not sure if that's possible right now
4) it would be nice to have built-in editor for equipment parameters,
5) it would be nice to be able to define set of unit properties for further usage, per unit type, and be able to use them as defaults for creating new units in scenario

Movement - complete control of each hex movement. I should be able to move to any spot within movement range w/o predetermined paths. Movement is achieved by one hex at a time with an overlay arrow pointing to each hex that the unit will move through.

Campaign - ability to bring war to the entire world. Add grand strategy like an Axis and Allies with regional/tactical battles determined by hex warfare, not die rolls. Ability to wage war in any territory in the world with prestige as an incentive/spoils. This would require improvements to air and sea combat. Incorporating procedural generated scenarios could make this possible.

WEATHER:
I would opt for a more dynamic way the WEATHER inflicts the battle. As of now, the changes are depending on a predictment, which sometimes is correct or not - as in actual weather forecast. So it has a true to life element of uncertainty.
But the current implications of (changing) weather conditions could he changed to a better true to life situation.
Weather conditions could be changed to more locally and changing with excecutive turns. We all now rain and snow storms sometimes inflict large zones, but also occur locally. Presently used maps represent an area that is too large to implement this.
Way not have rain/snow storms represented in (lets say) 10x10 hex formations which travel across the map like in real time. With algorithms changing direction, speed, strength, etc., so there is no prediction each time we play this map. And with changing consequences: one storm may prevent use of airforce alltogether - causing airplanes to avoid the storm and take a detour to their destination. In this way not the entire map is affected by the weather, but only locally - more true to life I think. This will allow airplanes to attack ground targets in some areas or not, instead of yes/no on entire map.
As for ground conditions due to the weather - again: in current mode the entire map is affected by one condition-for-all. Again - the entire map represents a too wide area to represent actual situation. Why not have similar changing/progressing ground conditions as weather conditions change position as turns pass by...

It would entirely change the way one has to direct its armies occording to arial cover... and change the way ground attacks can be supported by aerial attacks...

Would appreciate:
-better overall control / view of statistics - for instance after each turn a summary of units that are low on ammo/fuel - would enable a quick (over)view of planned attacks etc.
-an F5 view with shortcuts to show all armor, artillery and infantry units - as well as air units (fighter/bombers) - would help me to check if I have covered all grounds

A better control / overview becomes more important after late 1942 / early 1943, when battles become more difficult...

Morale is a good idea to implement. With the ability to regain morale by resting for a turn.

But most important is a better A.I that uses all its troops in cooperation in a map and not singe echelons fighting the human player one at a time. The A.I always have more untis. Surely an effect of the less competent A.I. Use most of your resources to improve the A.I. Personally I cannot care less for a new graphical upgrade or engine. I want better A.I and new features. In that order.

If it hasn't been mentioned earlier, I'd like to suggest that PC2 has a Random Mission Generator option.
Many other tactical wargames have it; you select map size, terrain type, force sizes and composition etc (or simply select "Random" for everything) then hit 'Go', and bingo, you find yourself on a fictional battlefield that you've never seen before, in command of a force mix you've never handled before, facing an unseen enemy force that could contain anything.
Our command ability to adapt and improvise to the unknown will therefore be tested to the full, how about it grasshopper?

PS- No offence to PC1, but after playing the same historical scenarios time and time again a touch of staleness begins to set in because we've seen it all before and things become a little predictable.
One partial way round it is to create our own scens in the excellent PC1 editor, the map will always be the same but we can assign a random "appearance chance" and a "hex location radius" to each individual unit so that every time we play the finished scen it's guaranteed to be completely different, and so is the weather.
For example if we assign a 50% appearance chance to say 6 enemy Tigers, each with a location radius of say 5 hexes, we'll find ourselves faced by 0 to 6 of them at various unknown locations and the tension level and replayability factor will be high each time we play.
Another option is to load stock historical scenarios into the editor and tweak them to our heart's content by slapping the aforementioned "appearance and radius chances" on all units to guarantee they'll be fresh and different each time we play them.
But having said all that, I still wish PC1 (and hopefully PC2) would have a random mission generator to cut out the need for all that fiddly tweaking..

I hope it's not too late to put forward some ideas for PC2. I am new to your fora, so please accept my apologies if any of those have been suggested already.
1. Enemy units previously revealed by recon etc. should stay revealed (but greyed out if possible) in hexes that are no longer visible in present turn. Therefore the enemy MAY still be sitting where previously spotted but the player cannot be sure as the hex is no longer visible. This eliminates the need for taking notes for what enemy units were spotted where.
2. Supply for buying or upgrading to newly-introduced or rare units should be limited. For example the player may have access to 2 new Tigers and 1 Panther but 6 Panzer IVs. When he upgrades a Panzer IV to a Tiger, the supply adjusts accordingly (1 Tiger, 7 Pz IVs). So no matter how much prestige the player has, he cannot field a dozen Tigers for an easy win.
3. When supply lines have been cut off e.g. nearby cities taken by the enemy and roads and bridges overrun, any isolated ground units should not be able to resupply. Also their fighting spirit should dwindle (-2 INI?).
4. The presence of adjacent friendly INF unit should increase the CD value of another unit engaging in combat in close quarters. So a tank unit attacking a city hex might have CD +2 when backed by infantry.
5. AA units shooting after moving should do so at half strength to reflect reduced time in taking aim.
6. Introduce scorched earth principle: retreating INF should be able to destroy own city or airfield so the advancing enemy cannot use it for resupply. ENG unit might be able to blow up bridges.
Looking forward to PC 2 in spite of 3D.

1. Give them more ammo when not deployed in the air
2. Allow them to have motorized transport that will be temporarily removed for the scenario if they deploy in the air

These will give paratroopers more flexibility, fun, variety, and usefulness outside of drop scenarios, which is historically canon as they were often used as general elite infantry.

Also often times their use is hampered even in drop scenarios as they don't gain enough experience beforehand due to being such a non-motorized liability. To balance these changes I suggest raising their relative price considerably as they come with their own planes and heavy training cost. Also perhaps lowering a stat or two depending on their ground ammo increase for number 1.

These are most likely major game engine logic updates and a decent amount of coding I imagine, but well worth it imo.

If still taking suggestions for consideration: a more versatile map.
At present we have the switch with F5, the birds eye view using the mouse wheel and the mini-map in the lower right of the screen.
Id like to have the ability to choose my own setting + or -. The overal map using F5 does not show the airfields and the mini-map hurts my (54 year old) eyes (although it does show the airfields).
In general the maps are a grey-greenish blur, with (rail)roads badly indicated.

Do you think it would be nice if those attacking animations came back from Panzer General?

With updates of course. Various animations if the defendant is not hurt at all, if dealt major damage, if it's utterly destroyed, if it routs. It would also be cool if the local terrain was shown as well.

Theoretically, these role are planned to be performed in the numerical order they are listed, i.e., 0 thru 9.

Also for your consideration:
Adjacent tanks provide mutual support (Screening) to infantry when the infantry are in the open (terrain)
Adjacent Infantry provide mutual support (screening) to vehicles in close terrain
Field Artillery can provide "Final Defensive Fires" (FDF) to any entrenched unit within range IF the artillery has also entrenched.
AT and AA artillery can provide mutual (overwatch) support to any unit if they are deployed and within range
NOTE: You should consider giving AT and AA artillery extended range (2 hex?) with reduced lethality since they are typically deployed over larger areas in smaller unit size units.

I would like to see Ports made more useful - at the moment it seems to make no difference if you land at a port or on a beach. Landing at a port could perhaps allow your unit to move on the same turn it landed. Also ports should be able to handle ships and land units in the same space like land and air units.

Amazing Revelation!!!...This was just "Too-Obvious" to be Noticed by Anyone!.

"vakarr"..."I would like to see Ports made more useful" - at the moment it seems to make no difference if you land at a port or on a beach. Landing at a port could perhaps allow your unit to move on the same turn it landed. Also ports should be able to handle ships and land units in the same space like land and air units.

Yes!, Port's & Harbour's were fervently sought after by all the Parties involved. I really detest, that in some games, a Landing is made and then the Unit immediately starts taking action to go in-land!. This is IMPOSSIBLE of course, I would very-much like to instead see that Port's and Harbour's are used to make the game more natural and Realistic.

Another possibility is that if there's a storm a proportion of your landing craft get damaged or destroyed, and only troops in transport ships can stay at sea, but maybe that already happens?

I would also like to see reconnaissance aircraft included - perhaps aircraft could have a dual role like AA guns, so they can be reconnaissance one turn and bomber the next - something like the Decisive Campaigns series, where you have to choose between sending a bomber on a recon mission or on a bombing mission. It seems dumb that your aircraft can't be used to remove the fog of war for that turn.

I like the idea of dual role for aircraft (recon vs. fighter/bomber) but would like the role to be only to be switchable when the unit is on an airfields, as with repair in PC1.

The switch could even change the stats of the unit in different ways, (depending on the unit?) which account for having to store camera equipment somewhere.
There could options like
a) All weapons replaced (attack 0, defense reduced)
b) Carrying less ammunition
c) Carrying less guns (reduced attack/defense and less ammunition).

As an alternative (or even additional) there might be a switch of "flight mode" which represents flying above or below the clouds. Of course you would have a better spotting if below the clouds, but would be more vulnerable to AA or fighter attacks (from above).